SLASF43 December   2023 AFE782H1 , AFE882H1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements
    7. 5.7  Timing Diagrams
    8. 5.8  Typical Characteristics: VOUT DAC
    9. 5.9  Typical Characteristics: ADC
    10. 5.10 Typical Characteristics: Reference
    11. 5.11 Typical Characteristics: HART Modem
    12. 5.12 Typical Characteristics: Power Supply
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Digital-to-Analog Converter (DAC) Overview
        1. 6.3.1.1 DAC Resistor String
        2. 6.3.1.2 DAC Buffer Amplifier
        3. 6.3.1.3 DAC Transfer Function
        4. 6.3.1.4 DAC Gain and Offset Calibration
        5. 6.3.1.5 Programmable Slew Rate
        6. 6.3.1.6 DAC Register Structure and CLEAR State
      2. 6.3.2  Analog-to-Digital Converter (ADC) Overview
        1. 6.3.2.1 ADC Operation
        2. 6.3.2.2 ADC Custom Channel Sequencer
        3. 6.3.2.3 ADC Synchronization
        4. 6.3.2.4 ADC Offset Calibration
        5. 6.3.2.5 External Monitoring Inputs
        6. 6.3.2.6 Temperature Sensor
        7. 6.3.2.7 Self-Diagnostic Multiplexer
        8. 6.3.2.8 ADC Bypass
      3. 6.3.3  Programmable Out-of-Range Alarms
        1. 6.3.3.1 Alarm-Based Interrupts
        2. 6.3.3.2 Alarm Action Configuration Register
        3. 6.3.3.3 Alarm Voltage Generator
        4. 6.3.3.4 Temperature Sensor Alarm Function
        5. 6.3.3.5 Internal Reference Alarm Function
        6. 6.3.3.6 ADC Alarm Function
        7. 6.3.3.7 Fault Detection
      4. 6.3.4  IRQ
      5. 6.3.5  HART Interface
        1. 6.3.5.1  FIFO Buffers
          1. 6.3.5.1.1 FIFO Buffer Access
          2. 6.3.5.1.2 FIFO Buffer Flags
        2. 6.3.5.2  HART Modulator
        3. 6.3.5.3  HART Demodulator
        4. 6.3.5.4  HART Modem Modes
          1. 6.3.5.4.1 Half-Duplex Mode
          2. 6.3.5.4.2 Full-Duplex Mode
        5. 6.3.5.5  HART Modulation and Demodulation Arbitration
          1. 6.3.5.5.1 HART Receive Mode
          2. 6.3.5.5.2 HART Transmit Mode
        6. 6.3.5.6  HART Modulator Timing and Preamble Requirements
        7. 6.3.5.7  HART Demodulator Timing and Preamble Requirements
        8. 6.3.5.8  IRQ Configuration for HART Communication
        9. 6.3.5.9  HART Communication Using the SPI
        10. 6.3.5.10 HART Communication Using UART
        11. 6.3.5.11 Memory Built-In Self-Test (MBIST)
      6. 6.3.6  Internal Reference
      7. 6.3.7  Integrated Precision Oscillator
      8. 6.3.8  Precision Oscillator Diagnostics
      9. 6.3.9  One-Time Programmable (OTP) Memory
      10. 6.3.10 GPIO
      11. 6.3.11 Timer
      12. 6.3.12 Unique Chip Identifier (ID)
      13. 6.3.13 Scratch Pad Register
    4. 6.4 Device Functional Modes
      1. 6.4.1 DAC Power-Down Mode
      2. 6.4.2 Register Built-In Self-Test (RBIST)
      3. 6.4.3 Reset
    5. 6.5 Programming
      1. 6.5.1 Communication Setup
        1. 6.5.1.1 SPI Mode
        2. 6.5.1.2 UART Mode
        3. 6.5.1.3 SPI Plus UART Mode
        4. 6.5.1.4 HART Functionality Setup Options
      2. 6.5.2 GPIO Programming
      3. 6.5.3 Serial Peripheral Interface (SPI)
        1. 6.5.3.1 SPI Frame Definition
        2. 6.5.3.2 SPI Read and Write
        3. 6.5.3.3 Frame Error Checking
        4. 6.5.3.4 Synchronization
      4. 6.5.4 UART Interface
        1. 6.5.4.1 UART Break Mode (UBM)
          1. 6.5.4.1.1 Interface With FIFO Buffers and Register Map
      5. 6.5.5 Status Bits
      6. 6.5.6 Watchdog Timer
  8. 7 Register Maps
    1. 7.1 AFEx82H1 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Multichannel Configuration
    2. 8.2 Typical Application
      1. 8.2.1 4-mA to 20-mA Current Transmitter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Current Loop Control
          2. 8.2.1.2.2 HART Connections
          3. 8.2.1.2.3 Input Protection and Rectification
          4. 8.2.1.2.4 System Current Budget
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Setup
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RRU|24
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.5.3.3 Frame Error Checking

If the AFEx82H1 are used in a noisy environment, use the CRC to check the integrity of the SPI data communication between the device and the system controller. This feature is enabled by default and is controlled by the CONFIG.CRC_EN bit. If the CRC is not required in the system, disable frame error checking through the CRC_EN bit, and switch from the default 32-bit frame to the 24-bit frame.

Frame error checking is based on the CRC-8-ATM (HEC) polynomial: x8 + x2 + x + 1 (9'b100000111).

For the output register readback, the AFEx82H1 supply the calculated 8-bit CRC for the 24 bits of data provided, as part of the 32-bit frame.

The AFEx82H1 decodes 24-bits of the input frame data and the 8-bit CRC to compute the CRC remainder. If no error exists in the frame, the CRC remainder is zero. When the remainder is nonzero (that is, the input frame has single-bit or multiple-bit errors) the ALARM_STATUS.CRC_ERR_CNT bits are incremented. A bad CRC value prevents execution of commands to the device, which prevents FIFO data from being lost as a result of an invalid read command.

When the CRC error counter reaches the limit programmed in CONFIG.CRC_ERR_CNT, the CRC_FLT status bit is set in the ALARM_STATUS register. The fault is reported (as long as the corresponding mask is not set) as an ALARM_IRQ on SDO during the next frame. The ALARM pin asserts low if enabled by the alarm action configuration (see Section 6.3.3.2).

The CRC_ERR status bit (see Figure 6-29) in the SDO frame is not sticky and is only reported for the previous frame. The ALARM_STATUS.CRC_FLT bit is sticky and is only cleared after a successful read of the ALARM_STATUS register. Read the GEN_STATUS, MODEM_STATUS or ALARM_STATUS registers to clear any sticky bits that are set.

The sticky status bits are cleared at the start of the readback frame and are latched again at the end of the readback frame. Therefore, if the fault condition previously reported in the status register is no longer present at the end of the readback frame, and the data are received by the microcontroller with the CRC error, the fault information is lost. If a robust monitoring of the status bits is required in a noisy environment, use the IRQ pin in combination with the status mask bits to find out the status of each fault before clearing the status bits. Set the CONFIG.IRQ_LVL bit to monitor the signal level on the IRQ pin, and unmask each status bit one at a time to retrieve the information from the status registers.